Sacrificial Composite Cell Structure for Constant-Force Crash Absorption
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Solution Overview
Problem
Current energy-absorbing crash control systems in vehicles, particularly those with constant collapse cross-sections, suffer from reduced stroke and increased force response due to increased contact surface area, leading to low energy efficiency during collisions, especially with cylindrical impactors.
Innovation Solution
A sacrificial composite part with cells having a peripheral wall thickness that decreases from the first end to the second end, along with an increasing internal cross-sectional area, and connected by elements with decreasing thickness, designed to maintain a constant penetration force and absorb energy efficiently during collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If assemblies with constant collapse cross-sections are used, then structural simplicity is maintained, but energy absorption efficiency decreases and stroke is reduced
Solution Approach 1:
The patent applies local quality by varying the wall thickness of individual cells along their length, creating zones of different structural properties. Specifically, cells have maximum wall thickness at their base and minimum thickness at their free end, allowing each location to perform its specific function: the base provides structural support while the thinner end facilitates controlled collapse and energy absorption during impact.
2Ease of manufacture
If constant cross-section assemblies are used, then manufacturing is simplified, but force response increases sharply during impact
Solution Approach 1:
The patent implements parameter changes by systematically varying the wall thickness parameter along the length of each cell. The thickness transitions from a maximum value at the base to a minimum value at the free end, creating a gradient structure that modifies the force-displacement characteristics during impact, resulting in a more constant and predictable force response.
3Loss of energy
If frustoconical cells with variable thickness are used, then energy absorption improves, but risk of wall rupture increases
Solution Approach 1:
The patent addresses wall rupture risk by applying local quality principles: thicker wall sections are positioned at the base where structural integrity and load bearing are critical, while thinner sections are located at the free end where controlled deformation is desired. This spatial variation in thickness optimizes both energy absorption and prevention of catastrophic failure.
4Area of stationary object
If cylindrical impactors are used, then contact surface area increases during penetration, but energy efficiency decreases
Solution Approach 1:
The patent counteracts the increasing contact area effect of cylindrical impactors by implementing parameter changes in the opposite direction: wall thickness decreases along the length of the cell in the direction of impact. This ensures that as the impactor penetrates deeper and contact area increases, the reduced wall thickness compensates by reducing the resisting force, thereby maintaining constant energy absorption efficiency throughout the penetration process.
Data Source
AI summary
The invention relates to a sacrificial composite part (1, 10, 100) that absorbs the energy released at the time of a vehicle collision with an impacting object (2), said part consisting of an assembly of a plurality of cells (3, 30, 300), each cell comprising a wall (5, 50, 500) connecting a first end (6, 60, 600) and a second end (7, 70, 700) of said cell, the direction of penetration (8) of the impacting object into said part going from said first end to said second end. Said sacrificial composite part of the invention is characterized in that that peripheral wall of each cell has a decreasing thickness (e) from said first end towards said second end of said cell, in the direction of penetration of the impacting object.